Understanding neuromusculoskeletal interactions underlying biomechanics and control of the human hand

灵巧的手功能是人类身份的一个决定性特征。从早上穿衣服到晚上准备晚餐，手在日常生活的几乎所有活动中都是至关重要的。完全对置的拇指对于手的功能尤其重要，它可以通过握力或捏合与物体和工具互动。虽然手的多功能性是现代人类创造力的一个中心主题，但它复杂的解剖结构挑战了我们对机械功能和神经肌肉控制的理解。一项手部密集型任务的成功完成最终依赖于神经生理(如感觉神经和运动神经)和生物力学装置(如肌肉和肌腱)的无缝相互作用。然而，迫切需要研究这些系统如何相互作用以保持手的功能，特别是在需要在线控制姿势和握力的复杂职业任务中。我的研究将使用一种创新的、跨学科的方法来研究手的生物力学和神经肌肉控制。这项研究将分为三个主题：(1)确定机械相互作用；(2)通过实验操作感觉运动通路来阐明生物力学和神经生理学之间的联系；(3)开发能够表示手内神经肌肉骨骼耦合的计算机模型。*第一个主题将研究手肌肉骨骼结构之间的力学相互关系。参与者将进行与职业相关的手部活动。测量将包括使用力传感器的握力，通过运动捕捉的关节角度，以及来自细丝EMG的肌肉活动，重点是外部(大)和内在(小)手肌肉之间的负荷分担。其他研究将使用电刺激来引起拇指肌肉收缩。超声将评估腕管(手腕)的大小和形状的同时变化，以及穿过手腕的解剖结构的机械特性。第二个主题将集中在感觉运动整合和当神经生理机制在短时间内改变时的适应。具体地说，将在对手腕施加压力之前、期间和之后对手的生物力学功能进行评估。这一主题的研究还将对视觉反馈进行实验操作，以确定感觉输入对生物力学功能和神经肌肉控制的综合影响。第三个主题将开发一个手的计算机模型，以结合从第一个和第二个研究主题收集的数据。这项创新的研究将评估生物系统中的冗余，为工业工程和人体工程学(例如工具设计)等几个重要领域提供信息，以提高工作绩效和效率。

Dexterous hand function is a defining feature of the human identity. The hand is vitally important in nearly all activities of daily living, from getting dressed in the morning to preparing dinner in the evening. The fully opposable thumb is especially crucial to hand function, enabling interaction with objects and tools via gripping or pinching. While the hand's versatility is a central theme in modern human ingenuity, its complex anatomy challenges our understanding of mechanical function and neuromuscular control. Successful performance of a hand-intensive task ultimately relies on the seamless interaction of neurophysiological (e.g. sensory and motor nerves) and biomechanical apparatus (e.g. muscles and tendons). However, there is an immense need to investigate how these systems interact with each other to preserve hand function, especially during complex occupational tasks that require online control of postures and grip forces. My research will use an innovative, inter-disciplinary approach to investigate hand biomechanics and neuromuscular control. This research will be organized in three themes: (1) Determining mechanical interactions; (2) Elucidating links between biomechanics and neurophysiology by experimentally manipulating sensorimotor pathways; (3) Developing a computer model capable of representing neuromusculoskeletal coupling within the hand.******The first theme will investigate mechanical inter-relationships between musculoskeletal structures of the hand. Participants will perform occupationally relevant hand activities. Measurements will include grip forces using a force sensor, joint angles via motion capture, and muscle activity from fine-wire EMG, with a focus on load sharing between the extrinsic (large) and intrinsic (small) hand muscles. Additional studies will use electrical stimulation to elicit thumb muscle contractions. Ultrasound will assess concurrent changes in the size and shape of the carpal tunnel (wrist) as well as mechanical properties of the anatomical structures passing through the wrist. The second theme will focus on sensorimotor integration and adaptation when neurophysiological mechanisms are altered for a short time. Specifically, biomechanical hand function will be assessed before, during, and after a compressive force is applied to the wrist. Studies in this theme will also experimentally manipulate visual feedback to determine the integrated effects of sensory input on biomechanical function and neuromuscular control. The third theme will develop a computer model of the hand to combine data gathered from the first and second research themes. This innovative research will assess redundancies across biological systems, informing several important areas such as industrial engineering and ergonomics (e.g. tool design) to improve work performance and efficiency.